The waters off North Carolina, a region long known as the Graveyard of the Atlantic, have claimed more than 5,000 ships over the centuries. The Outer Banks, a chain of narrow, sandy islands separating the Atlantic Ocean from the mainland, sits at the center of this dangerous stretch. To sailors, the area has always been treacherous. To locals, it has been a source of livelihood and legend.
The islands themselves are not stable landmasses. They are barrier islands composed primarily of sand, constantly reshaped by ocean currents and storms. Their position places them at a collision point between warm water from the Gulf and cold water from the north, creating shifting sandbars and strong currents that are difficult for ships to navigate. Shallow water that is not visible from the surface, thick fog, and sudden storms add to the risk, and the unpredictable conditions have been a hazard for vessels of every type.
Because of the constant movement of sand and water, the geography of the Outer Banks changes over time. Hurricanes have periodically cut new inlets through the islands, at times washing away roadways and isolating residents. In 2003, Hurricane Isabel cut a new 1,700-foot inlet that submerged a section of highway, and a new island that appeared off Cape Point in 2017 disappeared within a year. The landscape is essentially on loan from the ocean, which frequently takes it back.
The area has a long history with piracy, scavenging, and shipwreck salvage. Blackbeard, the most well-known pirate of the American coastline, operated in these waters in the early 1700s. His flagship, the Queen Anne’s Revenge, sank in 1718 and was discovered by divers in 1996. Salvaged artifacts, including cannons and gold dust, have since been recovered. Locals historically made a living from whatever the sea brought ashore. Survivors of a shipwreck in 1889 used timber from their vessel to construct the village of Wash Woods, building homes, a church, and a school from the reclaimed wood.
One of the region’s most persistent legends involves Nag’s Head. According to local folklore, wreckers tied lanterns to the necks of horses and walked them along the dunes at night. From offshore, the bobbing lights appeared to be other ships in safe water, and captains who followed them would run aground on hidden sandbars. Historians have found no solid evidence that this occurred, but the story remains a popular part of coastal lore.
Modern wrecks have continued to occur in the region. In 2012, the tall ship Bounty sank off the coast during Hurricane Sandy, and in 2020, a commercial fishing vessel named Ocean Pursuit ran aground near Bodie Island and was left in place. Many older wrecks remain buried beneath sand or underwater, and archaeologists continue to find new ones, both as technology improves and as shifting storms expose what was previously hidden.
Despite the dangers, the route remains in active use. The Atlantic coast of the United States is a major shipping corridor, and the Outer Banks sits along the natural path between northern and southern ports. The ocean routes provide significant cost and time savings, so cargo vessels continue to pass through the area with the assistance of modern navigation technology.
Underwater avalanches, known as turbidity currents, are another powerful force present in the oceans. These rapid, downhill flows of sediment-laden water can travel great distances and cause significant damage. An event off the northwest coast of Africa, which began as a small landslide in the Agadir Canyon roughly 60,000 years ago, grew more than 100 times in size as it moved across the Atlantic Ocean floor, eroding hundreds of feet into the canyon walls and damaging a total area of more than 1,700 square miles.
A more recent example of this phenomenon occurred on January 14, 2020, when a turbidity current travelled more than 680 miles from the Congo River estuary. The flow was set in motion by severe flooding along the river and large spring tides. It carried a volume of sediment equal to about one-third of the total annual sediment output of all the world’s rivers. The avalanche broke two seabed telecommunication cables, interrupting internet data speeds across West, Central, and South Africa.
Underwater avalanches can be triggered by earthquakes, typhoons, high tides, river floods, and volcanic eruptions. Their triggering events do not necessarily relate to their scale. A powerful earthquake off Portugal in 1755 triggered a small underwater avalanche, while an earthquake off the coast of Newfoundland in 1929 triggered the largest underwater avalanche ever recorded, which travelled at high speed and snapped 11 seabed cables.
Researchers have studied these events using sediment samples, seismic data, and ocean floor mapping. In some cases, they have reconstructed past avalanches to understand how they develop. The findings indicate that a modest event can grow into a large and destructive flow. Scientists have also recreated these currents in laboratory settings to observe how they interact with features like miniature basins, which can influence how the sediment is deposited.
Because undersea cables are essential to global communications, the breaking of these cables has significant consequences. In 2006, an earthquake in Taiwan triggered underwater avalanches that cut cables connecting Southeast Asia with the rest of the world, causing major internet service disruptions across several countries.
Sea levels are also expected to continue rising in the coming decades. The rate of global sea level rise has doubled over the past three decades, primarily due to the warming of the planet. Melting ice in the north and south poles, combined with the thermal expansion of warmer ocean water, has contributed to this trend.
According to projections, sea levels could rise by around 6 feet by the year 2100. Coastal flooding is expected to become more common during this period. Several areas, including parts of Florida, Louisiana, California, and Washington, are considered likely to be among the first in the United States to feel the effects.
Other countries face a more immediate threat. Nations such as Fiji, Vanuatu, the Marshall Islands, the Solomon Islands, and Tuvalu, many of which are comprised of low-lying islands, are considered highly vulnerable. Some Pacific communities have already relocated residents to higher ground, and others are reinforcing shorelines with stone walls and mangroves to reduce the impact of waves.
Scientists are examining a number of potential responses to rising sea levels. One of the most ambitious proposals involves a large structure near the Thwaites Glacier, also known as the Doomsday Glacier, located in West Antarctica. The glacier already contributes to about 4% of global sea level rise each year, and its melt rate is accelerating. Engineers have considered building a large underwater curtain, roughly 50 miles long, anchored to the seafloor, to block warm water from reaching the base of the glacier.
The construction of such a structure would require autonomous drones rather than human divers, due to the extreme depth and pressure. The project would come with an estimated cost of around $80 billion and present major logistical challenges. There are also open questions about its potential environmental impact on local marine life and nutrient flows.
Even if such a curtain were built, it would only address a single part of the problem. Ocean levels rise from multiple factors, including the melting of the Greenland ice sheet, mountain glaciers around the world, and the expansion of seawater as it warms. A storm surge on top of a higher baseline water level can push flooding further inland.
The Cascadia Subduction Zone, a fault line running from Northern California to Canada, is another area of continued geological and scientific interest. The zone is capable of producing major earthquakes, and records from the seafloor show a repeating pattern of quakes. Evidence suggests that these faults have sometimes ruptured in sequence. A large event in 1700 sent a tsunami across the Pacific that struck Japan, where it was recorded as an orphan tsunami because no one felt the earthquake that caused it.
Scientists using ocean-floor scans have found evidence of past events that produced underwater landslides and changes in the seabed. Large earthquakes in the region can cause the coast to drop several feet and generate tsunamis that can arrive within 15 to 30 minutes. With ongoing research, scientists continue to study the fault system’s behavior and its potential for future events.
While the possibility of major earthquakes exists, researchers also point to the region’s history and preparation. Studies of past events have led to improved building codes, emergency planning, and public awareness. Japan’s experience with the 1995 Kobe earthquake, which caused significant damage and economic disruption, led to an overhaul of that country’s disaster management systems and building standards.
The ocean floor itself remains a largely unseen and unknown part of the planet. Scientists have explored less than a small fraction of it directly. Underwater exploration has revealed unusual phenomena, including springs of fluid leaking from the seafloor along the Cascadia Subduction Zone, where the water acts as a lubricant between tectonic plates. Seismic surveys have also found evidence of microbial life in the rock of the oceanic crust, which appears to run on chemical reactions rather than sunlight, and some researchers believe this hidden ecosystem could be one of the largest on Earth.
Rogue waves, long dismissed as sailor exaggeration, have been confirmed by modern measurement. A wave recorded at the Draupner platform in the North Sea in 1995 measured 84 feet tall and was the first to be officially recorded. Since then, satellite data and weather buoys have shown that very large waves are more common than previously thought, and researchers have also documented the existence of deep, sudden dips in the ocean surface known as rogue holes.
The ocean is also home to a great deal of unexplained sound. Some low-frequency noises have been recorded at depth and are believed to be connected to the movement of large groups of animals, though researchers have not yet identified a specific source. The planet’s crust itself produces a constant, faint hum that comes from ocean waves, and satellites have helped track other anomalies over large areas.
The Southern Ocean, which surrounds Antarctica and is the youngest of the world’s oceans, has its own distinguishing characteristics. Its powerful circumpolar current flows eastward around the continent and connects the Atlantic, Pacific, and Indian Oceans. It helps drive the global system that redistributes heat, carbon, and nutrients. Scientists have observed that this current is slowing down as fresh water from melting ice mixes into the ocean. A weaker current can affect nutrient cycling, marine ecosystems, and weather patterns around the world.
